title: Regulation of ubiquitin-dependent cargo sorting by multiple endocytic adaptors at the plasma membrane.
abstract: Endocytic protein trafficking is directed by sorting signals on cargo molecules that are recognized by cytosolic adaptor proteins. However, the steps necessary to segregate the variety of cargoes during endocytosis remain poorly defined. Using Caenorhabditis elegans, we demonstrate that multiple plasma membrane endocytic adaptors function redundantly to regulate clathrin-mediated endocytosis and to recruit components of the endosomal sorting complex required for transport (ESCRT) machinery to the cell surface to direct the sorting of ubiquitin-modified substrates. Moreover, our data suggest that preassembly of cargoes with the ESCRT-0 complex at the plasma membrane enhances the efficiency of downstream sorting events in the endolysosomal system. In the absence of a heterooligomeric adaptor complex composed of FCHO, Eps15, and intersectin, ESCRT-0 accumulation at the cell surface is diminished, and the degradation of a ubiquitin-modified cargo slows significantly without affecting the rate of its clathrin-mediated internalization. Consistent with a role for the ESCRT machinery during cargo endocytosis, we further show that the ESCRT-0 complex accumulates at a subset of clathrin-coated pits on the surface of human cells. Our findings suggest a unique mechanism by which ubiquitin-modified cargoes are sequestered into the endolysosomal pathway.
authors.affiliation: Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53706, USA.
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Mayers
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.forename: Jhuma
authors.initials: J
authors.lastname: Pramanik
authors.forename: Adam
authors.initials: A
authors.lastname: Johnson
authors.forename: Ali
authors.initials: A
authors.lastname: Sarkeshik
authors.forename: Yueju
authors.initials: Y
authors.lastname: Wang
authors.forename: Witchuda
authors.initials: W
authors.lastname: Saengsawang
authors.forename: John R
authors.initials: JR
authors.lastname: Yates
authors.forename: Anjon
authors.initials: A
authors.lastname: Audhya
mesh_terms: D033942:Adaptor Proteins, Vesicular Transport / Q000378:metabolism*; D000818:Animals; D017173:Caenorhabditis elegans; D002462:Cell Membrane / Q000378:metabolism*; D004705:Endocytosis / Q000502:physiology*; D056827:Endosomal Sorting Complexes Required for Transport / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D006367:HeLa Cells; D006801:Humans; D047468:Immunoprecipitation; D013058:Mass Spectrometry; D034622:RNA Interference; D025801:Ubiquitin / Q000378:metabolism
chemical_list: D033942:Adaptor Proteins, Vesicular Transport; D056827:Endosomal Sorting Complexes Required for Transport; D025801:Ubiquitin
keywords: clathrin; multivesicular endosome